Akamai: Why Our IPv6 Upgrade Is Harder Than Google's

Akamai says one of its key engineering projects for 2010 is revamping its massively distributed network infrastructure to support IPv6, the long-anticipated upgrade to the Internet's main communications protocol.

However, Akamai says its IPv6 software development and testing project is proving more difficult and taking longer than IPv6 efforts touted by Google and smaller content delivery network (CDN) rivals such as Limelight Networks due to the complexity of the algorithms and home-grown software that it uses to distribute Internet content close to end users.

"We're not just racking and stacking standard Cisco boxes and operating systems and making some tweaks to some applications to have IPv4 and IPv6," explains John Summers, a senior product line director for Akamai who is managing the company's IPv6 development effort.

"What we do in our mapping infrastructure is to build a performance map of the Internet. A lot of what we do for our content provider customers is provide superior performance by providing route optimization across the fabric of the 12,000 service providers that are the Internet. Those mapping algorithms are pretty complex. Extending those mapping algorithms to the IPv6 space is difficult. As IPv6 rolls out, it's going to roll out in pockets, and that's going to make the routing around congestion points that much more important but also that much harder," Summers adds. "What we're solving is a much more complex problem" than Google's.

Akamai says it will complete its IPv6-related engineering effort later this year, and that it will begin a beta program -- dubbed a technology preview -- for select customers by the first quarter of 2011. Akamai plans to have commercial IPv6 service available to all of its customers in the second half of 2011.

"IPv6 is going to be a problem for our large content customers in the back half of 2011. We need to have the core delivery service available in that timeline," Summers says. He adds that the company is approaching IPv6 methodically and carefully because "what we do with IPv6 has to be every bit as bullet-proof as what we've done in the IPv4 address space."

Akamai's IPv6 efforts are significant because the CDN carries such a large share of the Internet's content. With customers such as the NBA, Clear Channel and Fox Interactive, Akamai delivers 15% to 30% of the Internet's traffic at rates that reach more than 4 terabits/second. When Akamai enables IPv6 services, many of the Internet's most popular Web sites will be able to support IPv6, too.

Akamai's experience with the next-gen Internet protocol runs counter to that of Google, an IPv6 pioneer that has claimed that its IPv6 development effort was easy and inexpensive. Google has been supporting IPv6 on its search, news, docs, maps and other popular services since 2009, and it IPv6-enabled YouTube in February.

Akamai rival Limelight Networks, a CDN that focuses on video content, demonstrated end-to-end IPv6 services with partners Comcast and Netflix in June 2009. Akamai says its network is harder to upgrade to IPv6 than Limelight's because it is bigger and more decentralized.

"Limelight has a more centralized infrastructure," Summers says. "We've got 75,000 servers, 1,000 networks, 1,500 different locations. That's really distributed. What we have to solve from a mapping perspective when I've got a dozen or 20 locations is different than if I'm serving IPv6 content from two or three locations."

Akamai customers demand IPv6

An increasing number of Akamai's customers have been asking about IPv6 support this year, Summers says. What's driving interest in IPv6 among content providers is the realization that IPv4 address depletion is real.

"We have 1,000 network partners, and we have to ask them for additional IPv4 addresses when they sign up with us. Some of them are telling us: "We're out,'" Summers says.

The Internet Engineering Task Force designed IPv6 12 years ago as a replacement to IPv4 because they realized IPv4 would eventually run out of address space. IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet. IPv6, on the other hand, uses 128-bit addresses and supports a virtually unlimited number of devices -- 2 to the 128th power.

The IETF's prediction of IPv4 address depletion is finally coming true. About 94.5% of IPv4 address space has been allocated as of Sept. 3, 2010, according to the American Registry for Internet Numbers, which delegates blocks of IPv4 and IPv6 addresses to carriers and enterprises in North America.

Summers says many of Akamai's customers are planning to offer IPv6 content to their end users in 2011, and they want to make sure that their CDN offers IPv6 support in that timeframe.

Akamai customers are demanding IPv6 service that is equal in performance to the company's existing IPv4-based services.

"Performance can get worse with IPv6," Summers says. "Filters break. Geo-location services break...Our customers want a minimal performance impact just because their end user is on an IPv6 address. We need to help them address the 'broken user' problem. Our end goal is native IPv4 and native IPv6 dual stack service that allows them to reach all of the eyeballs on the Internet."

Akamai says one key challenge is upgrading its home-grown mapping software to support IPv6 addresses as well as IPv4 addresses.

"We use DNS as a way in which a customer site comes into the Akamai platform. The customer's IP address resolves to an Akamai IP address, and we map that request by a browser to an edge server that's as close as possible -- generally one network hop -- to that user," Summers says. "The mapping algorithms we use are all built around IPv4 addresses. Now we have to do the same sort of IP mapping with IPv6 addresses, which are much bigger and the computational space is larger."

Summers says Akamai also has to upgrade its logging system to handle IPv6 addresses, as well as its geo-location services and its traffic reporting systems.

He says Akamai will offer IPv6 service in a few dozen locations by year-end. So far, Akamai is not having trouble purchasing IPv6 connectivity from carriers to support these locations.

"We have goals to acquire a certain amount of IPv6 bandwidth in a certain amount of IPv6 locations, and we're ahead of plan," Summers says.

Summers says that Akamai's IPv6 engineering effort, which began earlier this year, isn't running into serious technical problems but that it is complex. For example, instead of dealing with regular DNS A records, Akamai has to deal with the Quad-A records required by IPv6.

IPv6 "impacts many of the software components of the platform," Summers says. "Across the organizations, it's a pretty good number of people who are involved. It's a project that has good visibility across the company. It's something we know we have to get done because our customers are going to need it in the coming years."

Akamai says it will support IPv6 in such a way that it requires no changes to its customers' network infrastructures and that it will be as easy to turn on as its existing IPv4-based service.

"We want to help our content customers deliver a quality end-user experience out to IPv6 end users without them having to make any changes whatsoever to their data centers to support IPv6," Summers says. "We are telling our customers to leave their data center in IPv4, and that we will speak to them on IPv4 and we will speak to the end user on IPv4 and IPv6, and that we will route around all of the IPv6 speed bumps."

Akamai's timeline for offering IPv6 service is in line with predictions by experts of when IPv4 addresses will run out in 2011. ARIN officials recommend that Web site operators enable IPv6 by Jan. 1, 2012 or risk frustrating end users with lower-grade service.

"We have 3,400 customers, and we know they are all going to need [IPv6] at some point," Summers says. "IPv4 and IPv6 will exist side-by-side on the Internet for a long time. We need to make this as seamless as possible on the part of the end user."

Having worked on IPv6 engineering, development, testing and quality assurance issues for nine months, Akamai is recommending that CIOs think seriously about not only supporting IPv6 but supporting it in a way that's equivalent to their IPv4 services.

"What will make IPv6 a tough transition is not about whether the switches and routers will handle IPv6. It's about the architecture that's in place to provide a compelling end user experience on IPv6 that's equal to what customers are getting on IPv4," Summers says. "End users are accustomed to a really good experience on IPv4. They're unlikely to accept degraded performance because they have a different address scheme. The network performance, availability and reliability need to be the same in IPv6 as in IPv4, and you need to think critically about how you're going to enable that."